


Her Omega

by OnyxSinz (OnyxianDrake)



Category: Undertale (Video Game)
Genre: "Gagging", Alpha Female OC, Alpha Papyrus, Alpha Sans, Alpha Stretch, Alpha/Beta/Omega Dynamics, Asexual Papyrus (Undertale), Beta Edge, Beta Red, Crying, Crying During Sex, Dubcon Kissing, Dubious Consent, Ecto-Genitalia (Undertale), Ecto-Vagina (Undertale), Exhibitionism, F/M, Fingerfucking, Kissing, M/M, Masturbation, Masturbation in Shower, Mating Cycles/In Heat, Minor Violence, Multiple Orgasms, Neck Kissing, No Ecto-Penis (Undertale), Omega Blue, Oral Sex, Orgasm Delay/Denial, Purring, Vaginal Fingering, a/b/o dynamics
Language: English
Status: Completed
Published: 2020-06-14
Updated: 2020-07-05
Packaged: 2021-03-03 20:40:08
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 15,000
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24711724
Author URL: https://archiveofourown.org/users/OnyxianDrake/pseuds/OnyxSinz
Summary: Blue was expecting a nice, quiet neighborhood for himself and the others to live. What he wasn't expecting was a mage Alpha to be living in the same area. Or for her to take an interest in him during her heat.But was that such a bad thing?
Relationships: Kustard, Papyrus/Papyrus (Undertale), Sans (Undertale)/Original Character(s), Sans/Sans (Undertale), Spicyhoney
Comments: 17
Kudos: 187





	1. Chapter 1

**Author's Note:**

  * Inspired by [The Soldier and the Carnal Skeletons](https://archiveofourown.org/works/18068075) by [Writers_War_Z0ne](https://archiveofourown.org/users/Writers_War_Z0ne/pseuds/Writers_War_Z0ne). 



> Note: This fic was inspired by The Soldier and the Carnal Skeletons, but only loosely, because of the A/B/O dynamics, how there is a scene in it I highly enjoy involving Blue and the reader, and the reader being a female Alpha. This is in no way following a similar plot to TSCS(?), so if you're here for that, sorry, it's not it.
> 
> (There will be an xReader coming soon inspired by TSCS as well eventually with an Alpha Female Reader, so keep an eye out for that if you're interested)
> 
> -
> 
> If you made it this far, please be warned, this is purely self-indulgent, unbeta'd smut with plot! There is not nearly enough dominant female content in the tags I find on Undertale smut, much less where one of the skelebois goes with a female genitals, so I decided to write what I wanted to read myself.
> 
> Some of the content warnings include dubious consent. This is a heat-focused fic, so most higher functions from one of the characters is impeded when smut happens. If you don't like this, don't read, because this garbage is my cup of tea and I'm pretty damn pleased with how it's going ^^
> 
> Warning aside, please enjoy if this type of content is also your cup of tea!

“Stars, we’re finally done,” Red groaned, dropping onto one of the two couches in the living room.

“We have yet to unpack, you lazy slob,” Edge sniffed, arms crossed and sockets narrowing as Stretch wrapped his arms around him from behind.

“Aw, c’mon edgelord, I think we all deserve a break,” The taller skeleton practically purred, pressing a chaste kiss to the mark on Edge’s neck.

Red snorted as Edge’s cheekbones bloomed with red magic and he avoided giving his mate any attention in reward to his comment, “Blue, please tell our brothers they’re being ridiculous.”

Blue looked towards the three as he paused, eyelights shrinking slightly as three other pairs of eyelights were focused on him now. One of the many picture frames were in his hand, taken from the box he had begun to unpack of his own accord. A nervous prickle began on the back of his neck while he glanced between them.

“...we...were unpacking all day,” Blue squeaked out. “...a break...would be okay…?”

Edge gawked at the smallest of the four as Red cracked up with bellowing laughter despite his brother’s expression immediately souring, twisting into a sneer as he flicked his hand, Red tumbling off the couch suddenly. The older skeleton’s laughter cut off for a groan, sitting back on his legs with a sharp glare of his own.

“I see how it is, get yerself an Alpha and now yer brother is just chopped liver, huh?” Red teased, Stretch having been snickering against Edge’s shoulder.

Edge’s face darkened with his furthering blush at the teasing, before it turned smug, “At least I have an Alpha mate; you’re still dancing on eggshells with Sans. Can’t muster up the guts to accept his mark?” He jeered.

Red flipped him the bird in return, “Fuck you, asshole, I ain’t got any guts ta muster.”

“Good one,” Stretch chuckled, grunting when Edge elbowed him in the ribs.

“Keep it up and you’ll sleep on the couch for the first time in this house.”

Stretch gasped playfully, “What? Babe, no, please, I love you, you can’t do this to me-”

“I can and I will-” Edge bit back, planting his hand firmly in the middle of Stretch’s face and pushing him away when he tried to begin speckling his face with kisses.

Blue just shook his head at the three, shoulders shaking with quiet giggles as he put up the last picture frame from the box. The decorations weren’t nearly done for the house, but after unloading the boxes all day, even his own bones were aching for a minute of reprieve. At least now the newly bought house felt just a smidge more homely.

“You know the break applies to you too, right, Blue?” Stretch commented after he’d pulled Edge into sitting down with him on the adjacent couch.

Blue glanced over after breaking down the box, Red having dominated the two seated couch once more, one leg dangling as he scrolled through his phone. Edge had begrudgingly sat with his mate, but despite the less-than-impressed expression, he seemed practically melted into Stretch’s side.

“Oh, um, yeah,” Blue replied, a faint blue flush spreading across his own cheeks. “I just- it’d be nice for the house to feel...like  _ ours  _ before bed, you know?”

“It’s only three o’clock, bro, we got a few hours to unpack a few things. Edge is going to want the kitchen put together for dinner soon anyways, just take a few minutes.”

Blue slowly nodded, hesitating before walking over and sitting down on the other end of the couch, despite the fact Edge and Stretch were practically sharing one cushion between the two, he kept his space. Red was the first one to dig out the remote from the bag they’d been put in, turning it on to a random channel before sneering at the human news popping up and beginning to look through them properly.

It was nice, being able to relax, but only sometimes. Blue knew Edge felt the same way, needing to be up and doing something, needing to feel like the time is being used productively. Although, Blue would disagree that taking thirty minutes in the shower every morning with Stretch would be considered productive. Alas, that was the consequence of being around either of the lazier older brothers sometimes.

Getting sucked into time consuming activities that were most definitely not productive, that is. Not the activities Stretch only brought Edge into the shower. Nope. Blue did not want to get wrapped up in that type of activity with Red, ever.

Despite the rough start at the beginning when all the...multiverses met, Blue knew Red and Edge weren’t nearly as bad as their first impressions had given off. With the both of them being Betas, and him an Omega, it had been...a rather hostile first meeting. Especially with Stretch being an Alpha, and having for years kept him away from other that had bad intentions.

The unfortunate reality for Omegas like him, it seemed. When their underground opened up it had been discovered they weren’t the only ones that had been trapped, as monsters had been brought to the surface once before. It hadn’t even been a month of Sans and Papyrus’ underground being on the surface before his and Stretch’s underground surfaced, and then Red and Edge’s followed two weeks after.

Blue remembered those first few weeks, humans being overly cautious and always citing they needed to have a “procedure” to their integrating madness, to “vote” upon the citizenships for monsters being granted, and then further permissions for housing and work. It was tiring, and he knew for Stretch it was even more exhausting than usual, having to deal with three times the amount of monsters thinking they could possibly take Blue as their Omega.

He shuddered at the thought; knowing there had been close calls when they first came up to the surface. Some Alphas thought they owned any Omega they could claim, that they had a right to try. Even some Betas would take Omegas for their own. It was so much different on the surface, because none of the humans followed their dynamics.

No Alphas, Betas or Omegas. Just...humans, relationships, easy to leave and make new ones or have multiple. Usually only Alphas could have multiple partners under their claim, but with the change in rules by coming to the surface, a lot of that had been turned on its head. Everything was on paper now, tracked and documented, the humans even had to modify their legal papers to accommodate multiple monster relationships.

No, Blue didn’t have to worry about thousands more Alphas, thankfully; they were rare already as they were, just like Omegas. Of the billions of humans out there, he only had to worry about the maybe couple hundred scattered mages that still existed. They, unfortunately, followed monster dynamics. Most assumed it was because of the magic link, but there wasn’t really a way to research it without getting involved in topics monsters weren’t ready to discuss with humans quite yet.

Blue was perfectly content with that fact. He didn’t have humans to worry about seeing him as an Omega, and his brother was almost always around to keep him safe. Maybe he’d find a nice Beta or Alpha eventually, one he could trust and one Stretch, Edge and Red wouldn’t rip to shreds. He doubted it, though. Most of their clones, or doppelgangers, or duplicates, or alternates or  _ whatever  _ they were, had gotten together, or were getting together.

He wouldn’t say it put an expectation on his shoulders, but it sure felt like it. Blue just...didn’t have that interest in any of them. Red and Edge tried their hand when their underground first came up, but Stretch had been quick to put them in their place. Sans hadn’t ever moved on Blue like that, or shown interest, and Papyrus being a Beta with  _ zero  _ interest in anyone in a non-platonic manner left Blue content alone.

“Blue.”

Blue snapped his attention over to whoever had said his name, blinking away the heavy drag of lethargy at his sockets. Yikes, he must be more tired than he had originally thought.

“Yes? Did you say something?”

While he was rubbing at his sockets, Red leaning on the back of the couch he had been laid out on not minutes before. Or had it only been a few minutes? He felt like it’d been longer than just a few minutes...that wasn’t what he planned.

“Edge was checkin’ out the community page, some of the neighbors are doin’ a cookout, barbecue, whatever thing. He suggested we should go, ya coming?”

“Um...yeah, that sounds good. Are we walking?” Blue asked, standing and stretching slightly, his back not appreciating the angle he had been dozing at.

“Yes,” Edge replied, cutting Red off, the shorter hanging his head with a disappointed groan at the thought of exercise, even if only to walk down the street.

“Are we supposed to bring something?”

“Edge made some fancy mac and cheese with what we had,” Stretch replied as they headed out the door, showing Blue the pan he had in his hands.

A blue flush rose to his cheekbones, the sun nearly on the horizon, and the day feeling faintly humid and warm, but with a nice breeze.

“Why’d you let me sleep so long?” He pouted, realizing just how much of the day had been wasted from his nearly two hour long nap.

Maybe it’d been closer to three hours? He had seen something about the sun setting early this time of year...but was five really late enough for the sun to set?

“You deserved it, plus you were really out of it, I dropped one of the pans and you didn’t even flinch,” Stretch snorted faintly, while Red barked a laugh.

“Not to mention Edge started getting onto him loudly before being loud while cooking, ordering Stretch ta get some stuff for him.”

Blue felt his blush worsen. Wonderful, now his brother had something to hold over him for being lazy, taking a two hour nap. Hopefully he’d forget about it soon.

“Hey, maybe you’ll find a friend or two your age,” Stretch commented, Blue nodding as he picked at his bandana.

“Most likely they’ll be humans, not many monsters seem to have moved out here,” Blue replied lightly.

“The city holds a lot more to do, but it’s better out here in a community and having some peace and quiet,” Edge hummed, not bothering to plaster on a smile like Red did as they approached the community center.

It was...not terribly crowded, from what Blue could compare to other crowds he’d seen. Most of the humans were grouped up, talking and eating at tables, a few still cooking on grills and some kids running around with a ball. Not terrible for a first impression of their neighbors.

“Hey there!”

Blue startled when a voice was heard very clearly past the chatter of the crowd, having kept close to his brother and Edge while the latter sat down the macaroni on a table. A human, perhaps around his age? Blue could never tell, slowed his jog over to them with a wide smile.

“You guys are the new move ins, right? I’m Easton!”

Stretch tilted his head in greeting, shaking the man’s hand firmly, “Stretch. This is Edge, Red and my brother Blue.”

Blue waved lightly, politely smiling as Easton greeted them all.

“Well, I hope you all enjoy the barbecue! We have these maybe once to twice a month, and we make sure to get everything cleaned up and quiet by ten. Otherwise, just have some fun, I know several people are eager to meet the new neighbors! So few people have moved out recently, much less moved in!”

  
  
  


Blue loved social gatherings, really, he enjoyed the chatting and friendly aura people gave off, but with his too long nap and only one box unpacked, he was feeling antsy to get home. Easton was nice to talk to, upon learning they were the same age, but he could tell Edge was just as, heh, on edge as he was. It was getting later, maybe seven or eight, not too late, but enough for most of the kids to be gone now.

Drinks had been brought out when the last kid under eighteen left, to which Stretch and Red had eagerly joined in with having. Blue preferred his simple water after one soda, thank you, and despite Easton getting a beer(which apparently both of them were one year too young to drink) he hadn’t fallen into the nagging from Red to just take a sip.

Blue got distracted when a new figure seemed to be joining the gathering. They were late, considering the barbecue was supposed to end in around two hours to leave time to clean up. They had something in their hands, maybe a platter for a dessert of some sort, and some of the lingering adults hollered loudly and hugged the...female? that had just arrived.

He was a little too distracted, as the smaller skeleton jumped when he felt a hand on his shoulder, sockets snapping up to where Stretch was standing behind him. The older brother was tense, giving a gentle squeeze to Blue’s shoulder as he rumbled faintly in his chest as a low warning.

“C’mon, Blue, time to go.”

“Oh, sorry, were you guys meaning to leave earlier?” Easton asked, surprised at the sudden appearance of the orange hoodie clad skeleton as well.

Blue was about to answer when the smell hit him, immediately grabbing his bandana to shove over his nose as Stretch squeezed his shoulder a little tighter.

An  _ Alpha, _ here? At a human party?! Humans didn’t even follow the dynamics-

Oh.

Blue’s eyes snapped to where the new woman was chatting with a small group now, blessedly kept distracted by the furthest table from them as he scrambled to get up from the seat.

Red and Edge were already down on the sidewalk, empty dish in tow, meaning they had fled the second Stretch caught scent. How could he have missed the overwhelming scent?! Was he really that out of it today?

Easton seemed to catch on finally, looking where Stretch was looking, eyes widening and mouth open in realization as he looked back at them.

“That’s my cousin, Onyx,” He cleared his throat. “She’s, uh, she’s really nice! Um, you probably can tell she’s a mage, or, er, an Alpha, but she isn’t, like, the stereotypical type! She won’t mind if one of you are an Alpha too!”

“Thanks, but we really need to get going,” Stretch replied, voice and smile tight.

Easton gave a small, stiff nod, “Yep. Got it. Uh, I’ll let her know you said hello? She’ll want to meet you guys...eventually. She’d kinda, uh...the President of the community,” He rubbed the back of his neck, face faintly flushed out of embarrassment.

“Duly noted,” Stretch replied, and off he led Blue, keeping himself between his younger brother and the newly arrived Alpha.

It wasn’t until they were home, with the door locked and Stretch making a round around the house after Edge had already done so that Blue went limp on the couch. His bones felt like noodles and his soul was flighty as he rubbed his sockets, allowing himself to relax. He didn’t even have a reason to feel concerned; she hadn’t approached them, and despite the scent, they wouldn’t have known otherwise.

No doubt the ‘Onyx’ girl could tell Stretch was an Alpha just as easily, and she hadn’t tried confronting him, didn’t try to establish they were intruding on her territory, none of it. Very little information remained of how mages acted under the dynamics, but it had to be similar to monsters, unless maybe it had changed over time? He sure didn’t know.

What Blue did know, however, was that he needed to be careful now. In his own space, his own home, he couldn’t trust going outside for a walk now without one of the others. There were too many unknowns to Onyx, they’d barely gotten a glimpse of her, it was dark and nothing but her scent had given her away, and it had been overwhelmingly strong when he’d caught wind of it.

“That was too close,” Stretch muttered, running his hands over his skull.

“No shit,” Red huffed in response. “She was barely twenty feet away, she  _ reeked  _ of her position and heat, dude.”

“I know! But that means she probably smelled Blue, too! She’s gonna know there’s an Omega in her neighborhood now!”

Blue was back to the present the minute he heard that word. Heat.

“What?” Blue asked, more of a squeak than his usual tone.

All three pairs of eyelights snapped to the smallest skeleton now, Red lounging on the adjacent couch, Edge pacing in the living room while Stretch was stiffly leaning against the wall.

“Yeah, you smelled her, Blue, that wasn’t just territory marking she was giving off,” Stretch commented, frowning slightly. “She’s in heat; and it’s  _ bad _ , that’s why we had to leave so quickly.”

Blue felt ten times more anxious now. An Alpha in heat? Running the community he, an unclaimed Omega, lived in now? That means he wouldn’t be safe for at least a week, a week every four months, he’d have to hide in the house, and that wasn’t even counting his own heats.

“But wouldn’t she have tried coming after me the minute she smelled me? If it’s that bad, then...she wouldn’t be able to just...talk with people, right?” Blue barely got out, swallowing with a dry click.

“I don’t know. Mage heats and dynamics might be different than ours,” Stretch sighed, flicking the lighter in his hand now.

“We’ll just have to talk to her,” Edge stated simply. “Tell her Blue is off limits.”


	2. Chapter 2

**Summary for the Chapter:**

> Onyx is a mystery to the skeletons, but she agreed she won't do anything to Blue, so he feels comfortable enough to hang out with Easton properly. Turns out that might have been a mistake, or perhaps not?

**Notes for the Chapter:**

> Still a heatfic, same warnings with altered mindset because of the reaction to a heat. This ended up longer than I thought it would, lol
> 
> Hope you enjoy!!! We already got some juiciness going on >v>

By some miracle, within the two weeks of being in the neighborhood, Blue hadn’t once ran into Onyx that entire time. His walks were monitored or accompanied, usually by Edge, because even as an Alpha his brother was too lazy to get up and move for that long. The first week had been the worst, sitting on edge, not knowing what house belonged to the Alpha that, from what Stretch has said, was still in heat.

The only reason it made sense for it to last that long was it seemed she didn’t have a partner, at least not one that Stretch or Red could identify. As much as Blue disliked the idea of essentially stalking someone they should be respecting the personal space of, because she could make their lives living hell if she so pleased. This wasn’t Stretch’s territory, and the older skeleton didn’t have any plans of attempting to make it as such.

They were only one of two households in the neighborhood that had monsters, and the other one was just a cross species couple where the monster partner had moved in. Blue both appreciated and disliked how humans dominated the space, because it was safer from a dynamics standpoint, even with a mage that just so happened to be an Alpha around. 

He didn’t have to worry about if there was more than one around, because the chances of two mages living in the same area was rare unless they were related. It was a different story for monsters, even though Alpha were just as uncommon, Omegas were even less common but their highly focused populace in one area made it more likely to have two or three Alphas around at all times.

So yes, Blue really  _ really _ appreciated the fact they had human neighbors around more than mages or monsters. It was safer for him, less stressful for his brother because he didn’t have to worry nearly as much.

What led to the focus of their concern was how little they knew about the Alpha in the community. Onyx was practically a ghost, even for being the supposed President of the community, meaning everything had to go through her for approval. Blue hadn’t seen her but maybe one other time since the barbecue, and even then it was from a long distance.

She had been out walking with Easton, the later having been making more of an effort to get Blue out and meeting some of the humans around their age as well. What had frightened him was how quick she had focused on him, even from practically across the neighborhood, easily ten houses away, he could feel the second her gaze was on him.

Edge had been able to tell just as quickly, and had immediately had them turn tail to lead him elsewhere to go for a walk so they didn’t have to get closer. Was it rude? Possibly, but Blue didn’t dwell on it much. He was unclaimed, and with Stretch’s protectiveness and his own uneasiness from previous experiences with Alphas, he wasn’t in a rush to see how she acted around him or treated him.

At least Stretch had managed at some point to speak with Onyx, and from what was relayed to him, she was frighteningly lucid for how deep she was in heat. Stretch could feel her body heat from two feet away, like she was a furnace or something, more akin to the heat Grillby would put off. How she could put off that much heat without dying like most humans could was a mystery, because it would be more obvious if she was a mage with something akin to fire magic.

Apparently her scent had been sickeningly overwhelming to Stretch as well, even as an Alpha. Onyx had noticed him reacting to it as well, and had apologized to him, so even she knew it was affecting others, but somehow it just didn’t seem to be affecting her. There had been no elaboration, just her giving a vague agreement she wouldn’t be attempting to take Blue.

Stretch had said she’d worded it weirdly, like she had something else on her mind to do with the topic, but hadn’t breached it with him at the time. Just a statement of “I won’t try doing anything to him that would hurt him or compromise his unclaimed status” and she’d just...left. Onyx had cited work, but once again came the mystery of not knowing where she worked, where she was the majority of the time, what house was hers.

This left him relying on the possibility of Easton giving him some answers today. He was Onyx’s cousin, afterall, even though they scarcely looked alike. Easton was more tan, and had a different facial structure compared to Onyx. Although, Blue couldn’t say that was a determining factor, considering how little he looked alike to Stretch even with them being brothers.

He’d pondered the idea that Easton could be adopted, or even Onyx, but considering they were just newly made friends, Blue hadn’t felt it right to ask about family things. Although, he had been invited to hang out, so maybe they could exchange questions about their species? It’d be interesting to learn more about not just what he should worry about from Onyx, but learn a little more about the species that dominated the planet.

Which led to where he was right now, knocking on Easton’s door and rocking back and forth on his feet until the door opened to the taller man.

“Wow, you’re like, right on time,” Easton commented, waving the small skeleton in.

“Do humans not arrive on the time they’re told to?” Blue asked curiously, stepping in and slipping off his shoes with the others at the door to be polite.

“Sometimes, depending on the person, I’ve had friends show up an hour early to even three hours late to hangouts sometimes.”

“...wow,” Blue mumbled, though wasn’t surprised, his brother was more like the latter sometimes if Blue or Edge didn’t drag him out to get there on time.

“Yeah, but it happens, no skin off my back. So, you wanna play some video games and order pizza?”

Blue scrunched his nose faintly at the mention of pizza, but he could make this one exception for the week of eating something less than healthy.

“Sure! Can we also talk about some stuff? I’ve been wanting to ask questions over things I’ve been curious about involving the community and humans in general!” Blue replied, putting on his relaxed and cheery smile as he joined Easton in the living room.

“Sure dude! Just shoot and I’ll answer what I can.”

“Someone said at the barbecue it’s not normal someone moves out or in around here, why is that?”

Easton hummed, turning on the tv and handing Blue a remote, “Oh, most people in the area move here for the schools with their kids, or college students, like me. They don’t usually plan on leaving until they’re graduated and move on to better opportunities. There’s not a lot of retirees around here. The couple that had the house before you guys were actually military, they graduated from the university here and then had to move on for work.”

Blue nodded as he listened, tilting his head curiously when Easton chose some type of racing game for them to play.

“This’ll be easier to play while we’re chatting,” He explained after seeing Blue’s look, the small skeleton nodding.

“How did your cousin end up running the community?” Blue asked once the first round started, realizing it was a pretty straight forward racing game, no wild tracks he needed to keep a lot of focus on.

“Hm? Oh, Onyx was voted into the President role by everyone. This place basically has a resident operated HOA, so there’s regulations and community areas that have a fee for upkeep. The previous board and president were old hags and were eventually voted out, and everyone chose Onyx because she didn’t partake in any of it, funny enough,” Easton chuckled, the first round finishing and moving on to another after Blue won. “Every final decision is done by her, usually swayed by a vote from the residents of the neighborhood, but with how she keeps to herself and stays so level-headed, people like her making the choices.”

Blue hummed to show he was listening, curious about hearing more over the fact, but knowing there was plenty of time for that.

“Onyx seems to be gone a lot to be running a community.”

Easton nodded, “Yeah, she does work a lot. She has around two hundred people working under her that she has to keep track of, being a mage and all.”

“What does she do to have that many people directly under her?”

“Part of the government, or military or whatever. There’s special units mages get hired into, depending on their training and affinity in magic. Onyx has a lot of magic backing her, and training from a foreign academy, because our academy sucks. That gave her a foot up, and the government wanted her to be part of the military in case of emergency and to train other mages what she knows.”

“Is that why she practically radiates body heat?” Blue asked, looking over as they finished the third round and it went back to the selection screen, Easton having ultimately gotten the most points. “Stretch talked with her last week, said it felt like he was standing next to a fire elemental.”

“Hm? Oh, definitely. Well, partly it’s her magic levels, but it’s also something else that I can’t elaborate on, Onyx is better at explaining it than I am. Hey, I’m going to be back real quick, I gotta take a piss.”

Blue scrunched his nose at the language, and the reminder that humans did happen to expel waste their body made, but nodded. He was thankful monsters didn’t have to do that.

He sat in relative silence for a minute, the music on the screen playing quietly on the game. Blue’s gaze swiveled to the door when he heard it unlock, however, and froze up when the scent wafted in first. Then Onyx came into view, shutting and locking the door behind her before she even bothered looking over.

They stared at each other for a long moment, Blue’s soul not knowing whether to do cartwheels or try to vanish despite not even being manifested in his ribs.

“...hello. You’re Blue, right?”

Blue snapped out of his horrified daze, face blooming with a bright blush as his own instincts seemed to settle on the worst reaction possible.

“Yeah,” He barely squeaked, legs pressed together tightly, thankfully his magic wasn’t summoned quite yet with how the strong scent beared down on his senses.

“Where’s Easton?”

“In the bathroom,” Blue tried not to breathe as much, he didn’t need it after all, but it was still uncomfortable to not do the familiar action.

His own soul felt warm, pulsing magic that was heating up in his joints and pelvis, an unwelcome result of realizing he hadn’t even smelled her scent in the house before. It had to be her place, right? Was Easton just living with her for college and hadn’t clarified on accident? There’s no way he left him here, alone, an unclaimed Omega in a room with an Alpha in heat, right? He was human, he couldn’t possibly understand the implications of doing that-

“Oh, hey, cuz,” Easton greeted when he came back from down the hallway.

Blue didn’t realize they had been staring at each other still until the sharp, icy blue orbs looked to the human and it felt like a trance had been broken. Onyx nodded, greeting him back with a soft murmur.

“I’m going to be upstairs for a nap,” Onyx hummed, walking past Easton, vanishing down the hall and upstairs, Blue assumed.

An unfortunate effect of such an action being his soul pulsing in disappointment at the quick dispersing of her heat scent, leaving his magic heated, throbbing and dying to form in his pelvis.

“Sorry, forgot to mention she might be back at any point. Her schedule is kind of jacked up,” Easton apologized, Blue simply nodding as they continued playing the racing game.

  
  
  
  


It was a few hours of gaming before Onyx reappeared, and Blue had been hoping he’d find an excuse to leave before she would. His magic had taken nearly an hour to settle back down, but was much quicker to react once more the moment her scent overtook the living room once more.

“I’m going to be making dinner, unless you plan on reheating the leftover pizza,” She hummed, obviously directing the comment at Easton, not even looking at the two as she slipped into the kitchen.

“Nah, I’ll make sure to get it put up in the fridge though!” Easton called after, apologizing to Blue and leaving the ended round on the continue screen as he grabbed up the two boxes and took them to the kitchen as well. “Hey! Blue! Do you wanna stay for dinner? Onyx is great at cooking.”

“That is a blatant lie,” Onyx remarked back.

“I promise she’s the one lying! We’re making turkey melts!”

“When did I say that?”

“You’re getting all the stuff out for them again,” Easton jested in return, popping back out of the kitchen, pizza having vanished.

“Um…” Blue wasn’t sure how wise of an idea it was to stick around, femurs crossed and pressed tightly together now that his magic had made it very obvious he wasn’t escaping the fact it was summoned this time. “I’d...I’d have to go home right after!”

Damn it, why was it so impossible for him to just turn someone down?!

“Great!”

...and that’s how Blue ended up trapped at the dining room table, Onyx keeping her distance, thank the stars, and Easton sitting right across from him. It felt awkward, but Onyx didn’t seem tense, only looking towards them when he and Easton were chatting, or when she was addressed. The scent felt like it was getting stronger, and so were his instincts in response.

Blue didn’t have to guess what was to become of his underwear when he got home, not with his painfully throbbing magic also being horrifically, embarrassingly and obviously wet. At least to him, Easton seemed oblivious, as a human would be, but Onyx seemed to be casting him more and more glances. If Easton wasn’t there, Blue wasn’t sure he’d be keeping his status of unclaimed in that moment.

He felt a sense of relief and disappointment, stupid instincts, when Onyx was given the dishes to take care of. Blue had hoped he’d be able to tell Easton he needed to go in a polite manner, but the human practically leaped from his chair when he looked at his phone.

“Shit! My shift starts in ten minutes, I’m so, so sorry, I gotta run.”

Okay, fuck Easton apparently. Not literally, but Blue, despite being a pacifist, would dearly have loved to strangle the man in that moment as he raced out, leaving Blue stunned at the table. Alone. In a house with an Alpha in heat.

Somehow he must’ve lost track of time, or something along those lines, because then Onyx was standing in the entryway to the kitchen, watching him.

Blue would never admit he could essentially feel his cunt gush just at having her attention on him. It wasn’t exactly a welcome feeling, it was unfamiliar, because Stretch hadn’t ever let him be around an Alpha in heat for so long, and usually one this deep into it wouldn’t be able to stay six feet away.

“-show you out.”

Blue barely caught what she was saying, blinking dumbly and swallowing the magic building in his mouth, “What?” He barely got out.

“I can show you out if you’d like. You don’t have to stay and wait to be told you can leave.”

Stars, how did she have this much restraint? Blue couldn’t tell if he’d like for her to break and just take him on the table-

No, he did not want that. It was the heat scent making him think that. He needed to leave and get home to take care of the issue alone.

“That would be nice, please. Thank you.”

As reluctant as he was to stand, wanting to whimper at the loss of pressure from having his legs crossed so tightly, he needed to get out before she possibly lost whatever control she had if she smelled his reactive arousal.

It was an awkward walk from the table to the door, feeling her eyes looking him over as she followed, much closer now, but still minding his space. Blue fought to pull on his shoes, avoiding keeping his back to her when he did eventually have to bend over to pull them on properly.

Finally, he went to open the door, mumbling some jumbled excuse and thanks for her hospitality and food-

Blue froze when he was pressed up against the door. She was silent, in her breathing, her movement, everything. His soul was now doing backflips in his chest, and when he gasped feeling her press her body flush to his back, all he could breathe was her scent. There was no air, just her, and the heat radiating hot and stinging against him. Stretch hadn’t been lying; she was practically scalding in temperature, but he couldn’t tell if it hurt or felt utterly blissful as his pussy clenched around nothing.

A shiver made its way down his spine when her breath wafted over his neck, and despite knowing he should be cringing away from her, keep her from marking him, his instincts instead had him baring the vulnerable vertebrae there to her with a soft whine.

She chuckled faintly, and he shuddered when he could practically feel the vibration from it against his neck. But she didn’t bite.

“So tempting...you smell so sweet,” Onyx purred, and Blue didn’t have the sense to question how she could do that as a human.

His soul was practically pleading him to push back against her, let her claim him, ravish him right there against the door if only to soothe the agony that was the unfulfilled arousal between his legs. Then she was gone, and he felt cold, but the door was open and he just...stood there, for a long moment.

Slowly he came back to his senses, turned his head around, wanting to give into his instincts and beg her to take him as her Omega. But she was gone, somewhere in the house, and he wasn’t so far gone as to go after her. Maybe if she had been there, Blue would’ve been doomed to his instincts.

But she wasn’t, and Blue made it a point to rush out of the house without even locking the door behind him. His soul was racing, not nearly done with making it well known he was still turned on, but just as fluttery and panicked as his mind as he raced home. He triple checked the lock the moment he was inside, panting lightly, bones rattling and feeling a cold sweat on his bones now.

“...bro, what the hell happened?” Stretch asked after a moment of stunned silence.

Blue’s gaze snapped over and he immediately stood straight, legs pressed tightly together as his entire skull turned his namesake.

“...Easton lives with Onyx.”

Stretch’s expression darkened, “Did she do something to you?” He asked, voice tight with concern and leashed protectiveness boiling over into anger.

Blue hesitated before shaking his head, “No, just got a little too close!”

Stretch didn’t seem convinced but slowly nodded, “Go take a cold shower.”

“Yep! Will do that now!” Blue bit out before he raced upstairs, accidentally slamming the door to his room and heading straight for the bathroom.

A cold shower sounded awful, but it would be a quick fix to his problem...which was caused by him being trapped with Alpha heat scent everywhere...being pressed against the door…

Blue shuddered as a roll of heat made his magic throb, eager to just be touched and pleasured, more specifically by the Alpha that caused it. But he left for a reason, he couldn’t risk it. Even if she was very in control during her heat, it could be a different story in the throes of pleasure, and he could easily end up claimed unintentionally, or intentionally on her part without asking him first.

So he stripped and stepped into a hot shower instead, moaning softly remembering how much heat Onyx had been giving off, how it enveloped him and dominated the air so much that it was all he could breathe. His soul had manifested at some point, leaving a white glow in his chest and a blue one in his pelvis.

He wasted no time, moving to sit on his knees on the floor of the tub, legs spread as he slipped his hand between them.

Blue didn’t often try to masturbate, not needing some unfortunate guest to catch the smell of his arousal, nor his brother figuring out what he’d been doing. There was also the fact he wasn’t terribly enthralled by the idea, he’d experimented and enjoyed doing it, but he didn’t need it.

It was a different story for now, however, because the moment he swiped his finger between the sopping wet lips of his cunt, he knew if Onyx had so much as rubbed up against him he would have been at her mercy for however long her heat lasted. He hadn’t even hardly touched himself and he wanted to sob at the intense need, clenching around emptiness when his instincts were dying for something to fill him up, to use him, to breed him.

That’s what Onyx would have wanted, wouldn’t it?

Blue could still taste her scent from when it was practically choking him, feel her heat as he slowly pressed two fingers into himself. The immediate relief and sudden surge of a need for  _ more  _ made him whine pitifully, panting with soft moans as he began thrusting. It wasn’t nearly enough, but it was for the moment, making his pseudo-nerves light up in pleasure as he curled his fingers and brushed them against that perfect spot.

He couldn’t cry out loudly without making his brother aware of what he was doing, but all he could think of was Onyx behind him, slipping her hand down his shorts and finding him drenched and needy just for her. The thought of her fingers being the ones inside him, scissoring and curling, teasing him further and further along to an orgasm.

Just a light brush of his thumb over his clit had him biting his tongue as he came hard, trying to move his fingers as his walls held tight around them was a chore, but the heightened sensitivity had him arching into the air for something to press back against despite there being nothing.

Bones still quivering from the most intense orgasm he’d ever experienced, Blue slowly came to. The water wasn’t scalding anymore, but it was still a nice heat as he slowly relaxed. Pulling his fingers out was a task, one that left him trying not to moan and whimper at the overstimulating friction it caused.

His magic didn’t disperse immediately like it usually would have after being satisfied. And stars, did he feel deeply satisfied. Remembering the fact he’d come to the idea of Onyx being the one fingering him to completion left his face warm with a blue blush to his cheeks. Despite having just orgasmed as well, his pussy gave a curious twitch at the idea of another round.

But Blue couldn’t afford to see her during her heat, though, especially not with Stretch going to be on the defensive after how he acted when he came home. He’d have to wait.


	3. Chapter 3

**Summary for the Chapter:**

> Blue's been suffering for a week, and he's desperate for any help he can get.

**Notes for the Chapter:**

> Same warnings, along with crying, exhibitionism and gagging/muffling someone with a hand.
> 
> Some real smut today folks c;
> 
> Hope you enjoy!

Blue shuddered as he blinked awake, sight blurry with sleep and feeling sluggish despite knowing he wouldn’t be able to fall back asleep again for a little while. A soft whimper slipped out before he could stop it, tearing up in frustration as he pressed his legs together, arousal throbbing within his magic. His entire week had been nothing but that, unfortunate arousal, unable to curb it past the first orgasm after that first day.

Instead he slowly sat up, wincing as he slipped off his bed, reluctantly getting dressed, hoping a walk would get him to sleep some more. He’d been trying not to tell Stretch or give away what was going on, but it was growing to be too much. Nothing had helped, no touching himself, or even sneaking a toy to his room out of desperation to get his need to die down.

Now, after a week of it, he was tired, achy and felt like his entire pelvis and genitals had been rubbed raw. Acknowledging what, or who exactly, he needed to fix it always made it act up worse. The thought of Onyx’s scent, or the day she’d pressed him against the door had his legs shake and soul pulse with need. Blue felt like he could cry from the situation, but then Stretch would know and would ask questions, and he couldn’t handle that.

No, a walk and then more sleep was all he could handle for the moment. Maybe in the morning Blue would be able to beg Stretch for help figuring out what to do, but not until he got a little more sleep.

Thankfully, slipping out of the house was easy enough. Red wasn’t on the couch for once and the tv was off, but Blue had made sure all locks and latches and hinges in the house were well oiled. Edge could barely stand it, but Blue couldn’t stand the squeaks, and the compromise of Edge adjusting to the silent doors was a blessing in disguise.

Outside there was a faint chill, but it was a relief to his warmed, sticky feeling bones. No matter how many showers he took, either his bones felt too warm and sweaty or his magic uncomfortably soaked through his underwear. There just wasn’t any winning for him that week, and he didn’t look forward to it lasting even longer.

Blue walked in relative silence, unbothered by the air conditioning units kicking on and making noise at different houses, or even a few crickets and his own footsteps. He was left to his own thoughts, and unfortunately they managed to wiggle their way back to the thought of the Alpha. Onyx.

He bit his tongue this time to keep a whimpery moan from escaping, having to pause and collect himself at the pulse of not only his soul, but the clenching walls of his pussy as well. Tears pricked his sockets as he forced himself to keep walking, just wanting to make it to the lake to try and relax. Blue didn’t even know if he did want to be touched by Onyx given the opportunity anymore, with how hypersensitive and agitated his magic had been. All he’d been feeling for three days now was raw agony anytime cloth rubbed against him between his legs, and trying to pleasure himself to get it to ebb had resulted in just trying not to cry when the arousal just made it worse.

The small skeleton almost hadn’t noticed someone else at the lake, had he not seen the small, flickering light in front of them, and he froze.

Blue...wasn’t that well versed in the people around the neighborhood past Easton quite yet. He didn’t know who could be out this late, or why they would be. What he did know was they seemed to have planned to be there, and had been there possibly a long while.

The flickering light looked like an old style gas lamp, something he’d only seen in movies, and it illuminated the blanket laid out over the grass. Whoever was sitting there had their legs crossed, arms resting on their knees and...seemingly meditating? Maybe...maybe he could sit and relax with them? Blue was curious as to why they were out as well, it was easily one in the morning, if not a little later. It would be a good distraction as well, even if it was painful to sit down.

Barely making it two feet, Blue froze when they turned and looked at him, breath catching in his throat at the reflective, bright blue eyes staring back at him in the dark. Half her face was lit up by the lantern, and he could faintly make out the deep purple of the short curls of her hair. But it was her, Onyx, and his magic practically went into overdrive, and had he been any less tired he might’ve been embarrassed over how it felt like he’d practically gushed arousal.

There wasn’t a single word between them, just her expression relaxing and one hand patting the spot next to her in invitation before she turned back to looking out over the lake. Or meditating.

Blue swallowed the nervous lump in his throat and made his way over, painfully slow to sit down, keeping at least a foot between them. The silence was...almost suffocating. What was suffocating, however, was the thick, heavy scent of her heat consuming the air around him, just like before.

He could feel the radiating heat from the side she was on. It wasn’t scalding, not like when she had been pressed against him from behind, but it was just as noticeable and obvious how hot her temperature must be running. Blue still didn’t understand the mystery of why exactly she put off so much heat, and she seemed so unbothered by it.

Blue couldn’t say he was unbothered, not in the least bit. His soul made it very well known all the way down to his throbbing arousal that he was  _ very  _ bothered by her scent, heat and proximity. Closing his eyes didn’t help, remembering how nice it’d felt imagining her touching him right after he’d gotten home that first day. Now he had a fresh reminder of her scent, the clean, sharp sting of eucalyptus and the muskier smell of something smoky.

“...you seem uncomfortable.”

Blue snapped out of his reverie to look over at her, nervous sweat starting on his neck, throat feeling dry suddenly as he opened and shut his mouth like a fish out of water, unable to find the words needed to tell her. But it didn’t seem like she was commenting out of concern, just an observation. Something she knew the cause of, but didn’t voice yet.

“My heat has been making you react?” She asked finally.

“...yeah,” Blue replied meekly, finally breaking eye contact to tug at his bandana. “...all week.”

A soft hum was all Onyx responded with, her own gaze turning back to the water, posture relaxing as she stretched her legs out, hands planted on the blanket to support her leaning back.

“Do you want me to help soothe it?”

If Blue didn’t know better, he would’ve thought he’d orgasmed right then and there from how his magic flared with arousal just at the thought of her touching him. He choked on his breath for a long moment, legs tightly pressed together as he rattled faintly, trying to regain his bearings.

Could he allow it? Let an Alpha he hardly knew touch him like that? She was in heat, she must be feeling the tug of wanting to pin him down, take him then and there, right? Another heady pulse of need spiked in his nether regions at that, wrenching a soft whine from him.

“...are you going to claim me?” Blue barely managed, breaths shaky and deep, trying to reign in the fact he wanted to beg her to just take him then and there, to soothe the deep ache to be filled and touched by her.

Onyx hummed faintly once more, and he glanced up hesitantly, realizing she wasn’t even looking at him, but the lantern in front of them.

“...I understand your fear. You’re unclaimed. An Omega,” She replied simply, not answering his question. “...no, I’m not going to claim you if that is not your desire.”

Blue’s soul nearly did a backflip in his ribs, relief washing over him, despite the nagging concern on if she was possibly lying to his face. He didn’t know her enough to tell either way, if she was lying or telling the truth, but he was getting to desperate to care. It was a dangerous game of chance, letting himself give in to her demanding aura of arousal and demanding submission of him.

He’d be trusting her to let him go afterwards, to let him not be hers forever. Could he do that? The moment he gave in...he’d be begging her to do anything she wanted. He’d heard of bad times from Omegas forced into roles they didn’t want, by Alpha who had no respect for them. In comparison to Underfell, it was less common in Underswap, but there was no...protections in place for Omegas. Once they were claimed, that was it...unless the Alpha died and they were taken by someone else, which was next to never done in recent time.

So...could he really risk it?

Blue’s soul and agonizing arousal said yes, and after the pain of the week, with no help from the Alpha responsible...he couldn’t say no. It was a risk, but he was taking it, his sockets brimming with tears as he slowly nodded, desperate to make it stop.

He was expecting to get flipped over and pinned to the blanket, dominated and used by her, however she saw fit. What Blue wasn’t expecting was the gentleness of her hands, not guiding him to lie down, but instead to sit in her lap.

Once more he was overwhelmed by just how searing the heat from her body was, a shock of near-pain before it felt like bliss, and he leaned back to be flush against her torso. Onyx didn’t even have to touch him for Blue to shove his shorts and underwear down, unbothered by the fact they were outside, that they could get caught or seen. It didn’t matter anymore, the painful throb when the cold air wafted over the burning magic making him whimper a soft ‘please’.

Blue almost wanted to cry when she didn’t immediately try touching him, upset she even  _ shushed  _ him before a soft purr reverberated behind him in her chest. Gentle and slow, she guided his legs apart as much as his shorts permitted. Trying to hitch his hips towards her hands didn’t help, the hot touch of her fingers gently squeezing the crests of his pelvis making him choke on a desperate sob.

She kept them there, rubbing soft circles with her thumbs. Blue could only squirm and whimper as soft lips pressed against his skull, Onyx slowly trailing them down the side of his face. A sharp pang of worry shot through his skull when she got to his neck, but even still he bared his neck to her the moment the heat of her breathe wafted over the bone there.

Onyx simply pressed a longer kiss there, hand sweeping down along the curve of his pelvis. Blue’s hands clamped down on her thighs, phalanges digging into the soft fabric of her pants as just that teasing touch had searing heat gathering along the front of his pelvis.

“Please,” He tried once more, tears escaping his sockets when her fingers barely brushed along his pubic arch.

She didn’t respond this time, just deepened her purr as if amused. Right as Blue was about to beg, a soft gasp escaped when she drew her tongue slow and rough across his cervical vertebrae. It was hot and pressing between the bones, sending sharp tingles of pleasure straight to his pelvis as it brushed over the magic connecting them.

Finally, one hand traced to the front of his pelvis, slow and burning against the deep ache in his bones. Trying to buck up against her touch was simply regarded with a low, rough chuckle from Onyx. All Blue could do was whine, the sharp, desperate sound long and drawn out, unable to voice how much he needed her to touch him properly.

Soft kisses speckled back up his neck, pressing against his jaw and then cheekbone. His eyelights were hazy and unfocused, but she was smirking when he tilted his head towards her, her own pupils blown wide.

The softest brush of her fingers over his clit had him burying his face against her neck, a harsh moan slipping through his teeth as he arched against her touch. A relieved sob escaped him when it didn’t stop, trying to keep his mouth shut as he panted and whimpered with the pleasure. A hot coil of want and need began to build in him the more she gently circled his clit, barely touching it, but her finger warm and slick with his arousal slowly pooling on the blanket.

Had he been anymore lucid, Blue would’ve been thoroughly embarrassed, but for now all he could do was moan and cry faintly as his walls throbbed and clenched around nothing. It wasn’t an orgasm, but he was nearly tipping over that edge of utter bliss, and if she would just  _ move her fingers a little lower… _

“Please,” Blue sobbed dryly, hitching his hips into her hand, but she simply moved with him. “Please...I need…”

He whined pitifully when she rubbed over his clit and stopped touching him, hand moving to his pubic symphysis, wetly rubbing and teasing the bone. It felt like fire on the brightly agitated bone, and as much as it shot the same heat straight into his cunt, it wasn’t anything close enough to get off with.

“What do you need?” Onyx purred, voice low and husky beside his skull. “Tell me, precious.”

Why was she so _ mean? _ Blue felt like he was the one in heat, uncontrolled arousal and boiling warm marrow in his bones with nothing but a need to be used on his brain. How was she not just taking him and using him? How was she so clear minded enough to tease him?

“Please,” He weakly tried again. “I...I need...please...I need them inside me...I-I want to...to be filled-”

Onyx’s purr turned nearly into a deep growl as her smirk turned into a wide, pleased smile, and whatever she said to him was lost to the wind.

Blue’s thoughts were thrown out the moment his magic was spread wide, Onyx having slipped her hand down as he spoke to press three fingers into him. It burned, a sweet, filling friction and stretch to his walls. He dug his phalanges into her thighs sharply, wailing out in pleasure and arching at the sudden bolt of molten release as Onyx covered his mouth with her free hand. 

All he could do was sob and moan, hips jerking with each movement of her fingers inside of him, curling and rubbing against the slick walls of his magic. He wasn’t sure if he wanted to get away from the overwhelming burning of the need for more, whimpering faintly as when she went to tug her fingers out to thrust again. The sharp, harsh pain simply sent another burst of pleasure straight to his soul.

Onyx wasn’t bothered by the new factor, her fingers restricted by the clenched pseudo-muscles of his cunt trying to keep her in. It wasn’t too hard to keep Blue quivering and moaning in her lap, the tugging making him clench harder, in turn making him moan and press into her hand.

She was having fun repeating the teasing, tugging sharply before pressing them deep, curling them deep inside and listening to him cry softly in the utter relief of his Omega needs being fulfilled. She was well aware of how vulnerable he was like this, lost to the feeling, limp other than for his reactions to her fingers and putting all his trust into her taking care of him.

The moment Onyx’s fingers brushed over the spot that made him squeal, deep and perfectly placed for her to make a target of, she decided he’d had enough reprieve from his first orgasm.

Blue shrieked into Onyx’s hand when she pressed deep and hard against his walls, making him babble and sob, squirming and arching as the hot, tight coil quickly started building again. He felt sore and raw, extremely sensitive and overstimulated as each thrust of her fingers both pulled at his walls and sent a piercing pleasure through his magic. He could feel the tears rolling down his cheeks, but he didn’t want it to stop, chest heaving with quick breaths and what little strength he had was being used to press into her hand each time she thrusted.

“Such a good little Omega,” Onyx crooned, right beside his skull, making him jolt in surprise and choke on a moan when he pulled away from her fingers. “You’re so close...so desperate…”

Blue shrieked into her hand when she thumbed his clit, rough and quick, the coil going from tightening to feeling ready to burst-

“Come for me, precious.”

Onyx watched as Blue arched beautifully while he screamed silently into her hand, feeling how he twitched and quivered around her fingers, gently teasing him as he came back down from the high. He was panting and crying softly, shuddering and whining when she gently, but firmly, pulled her fingers out with seemingly little trouble despite how harshly it pulled his aching walls.

“That’s it, Blue, just relax,” She cooed softly, pulling him more bridal style into her lap, Blue eagerly curling up.

“But you…”

“Don’t worry about me,” Onyx hummed. “Sleep.”


	4. Chapter 4

**Summary for the Chapter:**

> Onyx gets interrupted at work, and has her first scuffle with an Alpha in years, while poor Blue suffers.

**Notes for the Chapter:**

> We're getting close to the end~!
> 
> I'm going to be writing the last chapter and my xReader idea at the same time before posting them, so it'll be like a double update~!
> 
> Hope you enjoy the chapter c;

“Get up! Do it again.”

Onyx watched with hyperfocus of each movement her two students made getting back into place. Weakness was to be exploited as far as they could get without hurting each other further than bruises. From what she could tell, Nora’s weak leg was starting to cause a limp, as much as she tried to hide it. Vanessa’s posture was lacking, which hinted to the fact her back was beginning to cause issues as well.

Regardless, she needed the two girls to be ready for any situation. Onyx disliked the government of her home country, but she hated her country’s academy even more. They severely lacked adequate teachers or funding to teach them even the most intermediate of magic, so her position being able to teach them not only combat made it impossible to turn down. She needed them to understand their magic like she knew her own.

“Archmage Onyx!”

Despite trying to stay expressionless as a stone wall at work, Onyx couldn’t help the twist of her mouth at being called out to. It would distract the two who were training...or help them learn to ignore outside influences if she did it properly.

“Focus! Do it again, now!”

She watched a moment longer as they started grappling again, no magic permitted, which meant she didn’t need to regulate much other than posture. And keep real fights from breaking out between them.

“Yes, Private?” She asked after glancing at the rank marking on his hat.

“There’s a phone call for you in the main facility, ma’am.”

“Is it an emergency?”

“Uh- not from what I understood, ma’am.”

“Then it can wait. You’re dismissed.”

“Yes ma’am.”

Onyx watched as Vanessa knocked Nora to the ground, only to be dragged down and land hard on her back, earning a grunt that was little more than an attempt to keep from shouting in pain. The fight was sloppy, slow and hesitant, both aching and tired from the five previous attempts to get their moves clean. Now it was just useless, teaching bad habits, pressing their resistance further than she needed for a basic go at hand to hand.

“Enough, we’re done for today.”

She almost laughed when Nora groaned and flopped back after straddling Vanessa, the two have basically been just weakly shoving and slapping at each other’s hands for control. Now they were both on the ground, draped over each other as they panted and seemed ready to die on the mat.

It truly was hot out, but her own magic regulating her temperature better than anyone in the state kept it from bothering her.

“Get up, stretch and then head inside. I have a phone call, and if I hear from anyone you two lollygagged, I will have each of you write a five page report on what you did wrong!”

That got them moving, albeit painfully, but it was better to stretch and get walking rather than lie down after such a long workout. For now she focused on heading for the facility behind her. At one point it likely had been a hanger, but now it essentially belonged to her for her unit. Very few mages bothered with the military roles in government, often going more for the political side to push their own agenda for academy reform and usage of magic in war.

To Onyx it was nothing more than laughingstock for the rest of the world, who were much better adapted to teach and use magic. It wasn’t on purpose, either, but it wasn’t an accident either to be so behind on mages’ teaching and roles in the military. The council disliked her country, and while they didn’t impede on their progress, they didn’t aid in it either.

Which made it all the more sweet, knowing she was the only Archmage in her country that would ever consider working with them. It made it impossible to get rid of her, impossible to remove her from her position of power because her years of expertise in a true academy would never match to a natively trained mage in their own academy. Her training was from out of the country, at one of the oldest magic academies in the world.

It wasn’t seen as prestigious by any means, but the teachings were old and proven to be effective. The problem with being trained there was the location, and the deep focus on their souls. Many older mages, and even new generation ones, were very hesitant to work with souls. Just as there was a taboo with monsters casually showing their souls, there was just as much of a taboo  _ learning  _ about them among mages.

Onyx really did feel privileged to have gone to the old academy, and being able to return to her home country, do what she could to teach younger mages what she knew felt just as much of a privilege. So she stayed in the government position, even if it had been served to her on a silver platter. No work had gone into earning the position among the military, but she was damn proud of her Archmage title, one she had quite literally killed for.

“I heard I got a phone call?” Onyx asked as she stepped into the area that served as her office, as well one for her ‘handler’.

Being her handler was a laughable title, considering she worked without a contract, and if they so much as gave her a small reason to leave, Onyx very well could. Not that she would, necessarily, but she didn’t take shit that wasn’t deserved.

“Yeah, it went to voicemail. Sounded like it was your cousin, he was talking about someone named Blue,” He replied, nodding to the phone on her desk.

Onyx didn’t keep it on her while working with her students, needing to keep her focus on them, especially when she was doing magic demonstrations. Small mistakes lead to big disasters was the general understanding of magic, and that was another reason she was left to her own devices for teaching.

Sitting down, she picked up the phone and started the voicemail, relaxing in her chair as Easton’s voice started.

“ _ Hey, so, I know you’re at work and you really really hate getting calls, but Blue’s here and uh...he doesn’t look too hot? Actually, uh, that’s kind of a lie, ‘cause he’s sweating like a fat man in a grey shirt on the beach. Anyways! He’s asking for you, and he seems about ready to cry, so, uh, call back when you can? _ ”

That was fifteen minutes ago, and she’d hardly been told about it but maybe ten minutes ago. Nothing too bad could be happening right?

Right as she was about to call him back, his name flashed up on the screen, calling her again. This time she answered immediately.

“Easton, what’s up?”

“Oh thank God you answered! Stretch is outside and he’s pissed and Blue is actually crying now, so I sent him to your room because his brother is, I don’t know, scaring the shit out of him? And me? I literally feel like I should just call the police because he’s slamming his hand on the door and yelling and uh, I don’t know if a neighbor might have called already but it’d be great if you could, oh, I don’t know, leave early for once in your damn life and come home-”

“I’ll be there in thirty,” Onyx sighed, standing and grabbing her back from under her desk, hurrying out of the office and for the exit. “If you need to, tell Stretch I’ll be there to talk soon. But do not, I repeat do not let him take Blue home if Blue doesn’t want to go.”

“Yeah...yeah, I got it. I’ll see you soon.”

“Don’t piss him off, Easton, he’s an Alpha.”

“I know! I’m not stupid,” Easton snapped, hanging up.

Onyx tossed her bag and phone into the passenger seat, starting it up and probably breaking the speed limit on the base to get out onto the highway.

Now, Onyx didn’t consider herself territorial by any means. She’d been around more mages than most could claim in their lifetime, which led her to have more experience around those who followed the dynamics. She didn’t have to adjust when the monsters came up, learn more about it like the humans did because the monsters easily outnumbered all the mages in the world.

But it also left her with special experience dealing with more Alphas and Omegas than she’d ever see in one place again. She didn’t need to keep a territory because she didn’t feel it was necessary with so few mages, much less Alphas, around. But now with Stretch and Blue, it was getting a tad annoying having another Alpha around. Tolerable, but annoying.

Although, she wouldn’t deny the Omega was worth it. Even if she was likely about to have a standoff with Stretch to get him to leave Blue where he wanted to be...the fact she knew Blue’s heat was kicking in was incentive enough.

Just the sight of Stretch at her door, arms crossed and obviously waiting for her had her own Alpha instincts kicking up. They were easy to ignore after years of doing it, but it was a familiar, and not unwholly unwelcome, nag at the back of her head as she got out of the car.

It wasn’t but two seconds later Stretch was shoving her against the wall of  _ her  _ house, on  _ her  _ territory, the one little place she considered to be specifically  _ hers  _ and something she would defend with her life.

“You need to back the hell up,” She growled lowly, hands grabbing his forearms firmly in warning.

“Not until I get my damn brother back,” Stretch spat. “ _ Let him go _ , you don’t deserve him and he doesn’t deserve to be owned for the rest of his life-!”

“It isn’t my intention to claim your brother, dumbass!” Onyx hissed.

“Then let me take him home!”

“Why don’t you fucking ask if he wants to go home?!”

Onyx glared at Stretch, his eyelights bright and teeth pulled into a snarl, “Then open the fucking door and let me talk to him.”   
  


“Fine!”

She shoved him off, swearing under her breath as she stalked up to the door, unlocking it and leaving it open as she stepped inside. Easton was on his feet from the couch in seconds, staring with wide eyes at the two of them.

“Where’s Blue?” Stretch demanded.

Easton opened and shut his mouth before clearing his throat when Onyx nodded, “Um, he’s upstairs.”

“Blue! Come down here,” Stretch called up.

Onyx listened quietly, tense and glaring at Stretch, Easton slipping out the door with a quick excuse of needing to get to work. Soft footsteps came slowly down the stairs before Blue was peeking around the corner, cheeks streaked with blue from his crying, face flushed and skull beaded with sweat.

“Blue,” Stretch started, “come here, we need to get you home.”

Blue glanced between him and Onyx, bottom teeth quivering, obviously upset and conflicted. She could already smell the sweet aroma wafting over, and while she’d deny the effects it had on her, she knew already that just the small whiff would leave her wanting more if he agreed to go home.

“I...I don’t want to…”

Stretch’s soft expression hardened again, “You don’t know what you want Blue, your heat is kicking in, it clouds your judgement and senses-”

“I’m perfectly capable of knowing what I want!” Blue whined, tears starting to build in his sockets again.

“If you let her take you during a heat she’s going to claim you! Do you want that?! To be an Alpha you barely know to rule your life?!”

“She’s not going to claim me!” He snapped back, hiccuping and rubbing at his sockets. “She didn’t do it in her heat, she’s not going to do it in mine!”

“She didn’t get the chance to-!”

“She did!” Blue interrupted again. “Several times! And I liked it, okay?!”

“... _ what? _ ” Stretch snarled, gaze turning to Onyx, a feral snarl on his teeth. ‘You bitch-!”

“No!” Blue wailed, lunging forward and putting himself between them, legs shaky and having to cling to Onyx for support, and comfort.

Onyx gently rested her hand on his shoulder, wanting to put him behind her to keep him from getting in the middle of a dispute between Alphas, but knowing it could upset him further.

“Just! Go home!” Blue hiccuped again, shaking with cries. “We’ll talk later, just... _ please _ , Stretch.”

Stretch gritted his teeth, still staring Onyx down, although she met his gaze head on as well, eyes yellow and pupils sharp slits in warning. He didn’t have enough time to question it, despite the sense of Blue being in more danger than he knew.

“We’re talking the minute he’s out of heat!” He growled, storming past and slamming the door behind him.

Onyx heaved out a sigh, blinking until her sight was back to normal as Blue sobbed against her shoulder. Gently she pulled him away to face him, wrapping her arms around him under his and nuzzling him.

“It’s alright,” She crooned, kissing his cheek softly.

Blue hiccuped faintly and nodded weakly, shuddering and pressing flush against her, burying his face against her neck, “Please...it hurts again...I tried to ignore it and it just got worse…”

Onyx purred softly, smirking and dropping her hold to around his hips and scooping him up, chuckling at his squeak and quick reaction to wrap his legs around her. She headed back up the stairs, speckling his cheek, jaw and neck with soft kisses as he squirmed lightly.

Kicking the door shut, she carried him over to her bed and gently laid him back on it, Blue letting her go and just sniffling at this point. Onyx smiled and pressed a kiss to his teeth, humming when he returned it.

The scent of his heat intensified when she easily tugged off and tossed aside his shorts, her own instincts rocketing off and deeply distracted with the need to do something about it other than kissing. Blue whined when she pulled away, but his legs fell apart easily despite the bright blush lighting up his cheeks as she moved to her knees between his legs.

Other than the night by the lake, Blue hadn’t been lucky enough to get a long enough private time with her for anything more than a quickie here and there. Onyx considered herself lucky, learning his morning schedule and catching him in private during his walks during the last week of her heat. Blue was left wanting each time, however, wanting to keep close to the Alpha and relax, but unfortunately she had to leave for work each time.

But now, Onyx took her time, brushing her lips over the summoned ecto of his thighs, ticklishly light and making him squeak in surprise when she playfully nipped him. Her chuckle made his blush darken, embarrassed and needing her to just touch him already.

“Onyx…” He whined softly, wiggling his hips and spreading his legs wider in need.

“Yes precious?” She teased, chuckling again when he whined as she repeated the slow kissing up his other thigh.

“Please…” He complained, shivering when he felt her warm breath on his sensitive magic. “I need you to touch-!”

Blue squealed when she leaned forward and dragged her tongue over his clit, phalanges bunching up the blankets of the bed in his fists.

A shiver raced up his spine when she chuckled against him, a soft moan slipping out at the feeling. She didn’t stop there to tease, circling his clit slow and gentle as he shivered and whined until she teased lower. Onyx slowly spread the lips of his soft, wet pussy open, deeply enjoying the scent and taste of the little omega as her tongue traced his slit. She hummed at the matching sweet taste of his arousal, smiling when Blue gasped at the sensation, back arching in pleasure.

Using a bit of her magic, it was easy to press her tongue deeper than she usually would try, curling it purposefully against that one delicious spot when she found it. The resulting cry was music to her ears, feeling his walls clench around her tongue and a sweet rush of arousal for her to enjoy was just another prize to her. Now, she focused, keeping her tongue against that one little place that had Blue moaning loud and sharp, his magic tensing and quivering as his pleasure built.

Onyx purred when he gave a wavering, airy moan when he came, humming and listening to his squeal from sensitivity as she enjoyed the sweet treat. It was just the first one of the night, and she easily slipped her tongue out despite how his magic was already clamping down hard out of the biological expectation of needing to keep whatever his Alpha gave him inside.

She stood from the ground, enjoying the scene of Blue looking up at her, eyelights hazy as he panted, shirt ridden up over his belly and ribs. The Alpha part of her was deeply pleased and ever more eager to continue the day with taking care of his heat, and her souls thrummed in agreement at the thought.

However, the sensible part knew that right now, she had to let him settle down. Unlike the times before, where she either left her fingers in him to tease him into another orgasm, or left right after, she wasn’t doing either. Instead she gently ridded him of his shirt, hands roaming his ribs and listening to his soft squeaks and giggles as she nuzzled and kissed his face.

“You’re so cute,” Onyx giggled softly, purring at the blush returning to his cheeks.

She moved them to sit at the head of the bed, letting him rest in her lap until he was ready again.


	5. Chapter 5

**Summary for the Chapter:**

> Blue has a nice morning and then the new couple has to deal with Stretch.

**Notes for the Chapter:**

> I didn't plan on posting this until I had the x Reader ready to be posted as well, but I'm struggling with it right now, so have this chapter while I have a fight with my ability to write! c:

Blue woke up slowly, bones aching and pleasantly warm. It felt nice to be so relaxed, feeling the press of Onyx’s torso behind him and arm draped over his waist as he tried to figure out what woke him up if it wasn’t an alarm.

A light, ticklish trail of the Alpha’s nails along his ribs sent a shiver up his spine, answering his question as he squeaked faintly. He could feel the heat of magic rising to his cheeks, squirming more as Onyx giggled behind him. But she didn’t stop, even teasing the underside of his ribs and making him jolt.

“Onyx!” He whined, trying to wriggle away from her assault.

“Where are you going?” She cooed, pulling him back against her easily with one arm, propping herself up with the other.

“Stop tickling me!”

Blue squealed when he felt her hand dip into his pelvis, the magic long gone, but the bone feeling starkly sensitive when she dragged her nails over his sacrum. She took advantage of his shock to continue teasing, gentle and relentless as she touched and teased everything she could.

He wasn’t trying as hard to get away now, despite the embarrassment over how quick his magic was reacting. His hips ached in mild protest, but when she tugged his pelvic symphysis and let go, his eagerness shined brightly in the form of his pussy.

The physical appearance of his arousal wasn’t missed by Onyx, her smile growing wide, fingers beginning to play with his clit gently.

“Onyx…” Blue whined softly, hesitating before spreading his legs with a shudder.

“Hm?”

He hesitated, weakly pressing down against her teasing, already wet with arousal from his Omega instincts happily giving in to the passive demands of her own Alpha presence.

“We’re supposed to...talk to Stretch- ah!”

Blue arched and clitted his teeth shut when she pressed a finger into him, whimpering softly at the sharp, overstimulating pleasure.

“I think he can wait,” Onyx purred, already teasing the rougher patch of magic that made up his g-spot, Blue squeaking with a soft moan as his soul and magic clenched from the pleasure.

He didn’t try speaking again when she started pulling out her finger before adding another, gasping when she spread him open, baring his neck when she ducked down to kiss softly at his neck. Idly he realized he wasn’t claimed still, and lost a tension in his bones he didn’t know was there.

Not knowing where to put his hands, he clung to her thin tank top, but quickly changed to scrabbling at her back. Three fingers, deep and rough into him had his magic protesting, adding to the heat coiling with pleasure in his pelvis. Tears were pricking his sockets, each moan sharp and wavery as he moved with her hand, desperate for the release that was just out of reach.

When Onyx’s teeth dragged slowly over his clavicle he flinched away, crying out when she pressed at that sweet spot hard and his orgasm crashed over him.

Blue shivered faintly when he came to again, humming weakly and pressing his legs together, pelvis tingling with lingering pleasure despite his magic being gone already. Soft, warm hands were roaming along his spine, the focus of heat in front of him where Onyx was lying with him still.

“You with me?” She chuckled softly, Blue feeling the faint rumble of a purr in her chest afterwards.

Blue hummed faintly in confirmation, snuggling closer to her warmth, mumbling, “That was mean…”

Onyx giggled, nuzzling the top of his skull, “Hm, I’m such a mean Alpha,” She crooned teasingly. “I won’t do it again.”

A hot blush rose to his cheeks again, “...I didn’t say...you shouldn’t do it ever again…”

“I’ll keep that in mind,” She purred loudly.

  
  
  
  


Blue couldn’t help smelling Onyx’s shirt after he slipped it over his head, cheeks flushed at the familiar eucalyptus and smokey scent. The smokey part still confused him, since he hadn’t seen her smoke ever, and from what he knew she didn’t work around fire.

“Your brother isn’t going to like you wearing that,” Onyx hummed as he came down the stairs.

“I’m going to smell like you regardless,” He replied, walking over to see what she was making, nuzzling against her arm.

The purring immediately started up the moment he touched her, to which he happily wrapped his arms around her hips, leaning into her warmth with a faint purr of his own.

“Here, you should go eat,” Onyx hummed, plating up the omelete she’d made, starting to make a second one for herself.

“But I want to eat with you,” Blue complained, reluctantly letting go, thanking her as he took the plate.

“I’ll be there in a minute, just please go eat.”

Sitting down, Blue pondered the tenseness in her tone at the last request for him to eat. He happily dug in after sitting down, watching her lose a tension in her shoulders when he did, and her gaze turned back to her own food. It was interesting, considering she hadn’t claimed him and yet she was acting like she had.

It was food for thought, but his stomach demanded he focused on the real food she’d made for him before they’d have to go face Stretch.

  
  
  
  


“Please don’t get into a fight,” Blue begged quietly as they approached the door.

“I'll try,” Onyx hummed, unconcerned.

The biggest thing that was nagging Blue’s nerves was how she just didn’t seem worried. Stretch was an Alpha, and then there was Edge and Red who were both Betas and yet she didn’t even seem irritated that they’d all moved into her territory? Her Alpha tendencies really confused him the more he tried to think about it.

After knocking he unlocked and opened the door, tentatively stepping in with Onyx on his heels.

Stretch was standing right in the front hallway, leaning on the kitchen entry, eyelights flaring with magic and exuding his Alpha aura, “Good morning Blue...Onyx.”

“Stretch,” She replied back simply, shutting the door behind her.

“Let’s talk in the living room!” Blue squeaked, already disliking the feeling of tension in the air between them.

“Sounds great,” Stretch bit out, pushing away from the wall and heading to the other entryway at the end of the hallway.

Onyx and Blue followed quietly, the latter fidgeting with his phalanges as they stepped into the living room. Edge sat tense on the far couch, Red sitting on the arm rest beside him, default grin tight.

“Might as well have bitten him with the way he stinks like you,” Red sneered.

“Red…” Blue chastised meekly, staying close to Onyx as Stretch sat down beside Edge, motioning to the other couch sharply.

“Sit. Let’s talk.”

Blue glanced at Onyx as she sat down, a small smile on her face, forced but relaxed to be polite. He knew she didn’t exactly have to cater to Stretch’s protective nature, but she was trying to do so to seem like she cared. Or maybe she did, but regardless, he knew the situation was dangerous for the both of them until they ended on similar terms. Hopefully.

“You’re not hurt? Unless she healed you before coming over,” Stretch started, tone practically dripping malice and contempt.

“No, I wasn’t hurt,” Blue replied back sharply. “Onyx wouldn’t hurt me.”

“Just because she said she wouldn’t claim you doesn’t mean she wouldn’t hurt you.”

“Well she didn’t! And she didn’t mark me either!”

“Yeah, and ain’t that just a mystery in itself,” Stretch snorted, gaze turning to Onyx now. “And why is that? Trying to get his trust so you can make him agree to being yours forever?”

Onyx’s eyes narrowed faintly, smile tightening, “Isn’t that how all relationships work?” She remarked, amused.

“Well, you kind of fucked that up quite literally when you let your heat affect him,” Stretch snarled.

“As if I had control of that?” Onyx laughed lightly. “Tell me, does your partner go unaffected when you’re in heat? What about his brother since you all seem to live so close.”

“I don’t use it to lure someone in.”

“I didn’t either,” Onyx hissed. “It wasn’t on purpose that Blue was around long enough for it to affect him. And I wasn’t just going to let him suffer in pain because of something I caused.”

“You could have marked and claimed him because of your heat! Did you not think of that?! You didn’t even try to get help, and it lasted a month!”

“I don’t need help. They’re mild, and I don’t care for any of the Betas I know.”

“Monsters have put places up for things like that to be helped-!”

“I don’t just walk in to a place to have heat sex and then leave,” Onyx interrupted. “Frankly, if it weren’t for the fact your brother got affected, I never would have. I did in fact see you all at the barbecue, just for your information. I kept my distance, let you leave without needing to talk to me. I wanted to talk to Blue after my heat, actually get to know him. I do want to claim your brother, but unless he wants it as well, it won’t happen. I don’t care if that’s weeks, months, years or never. But in all honesty, I’m just being courteous letting you know this, because it’s none of your business.”

“So you admit you want an Omega,” Stretch snapped.

“Every Alpha wants an Omega, and some get greedy and try to take more than one,” Onyx sneered in response. “I know that’s what scares you; your brother forcefully being taken by an Alpha. I’ve seen it happen between Mages. I know it happens between monsters. Neither of us is perfect, but I’m not going to try and force Blue to be mine. I think these past two weeks should count for something, considering I didn’t take him in my heat, nor in his. I even helped Blue through his, and yet he’s here, unharmed, unclaimed.”

“You’ve barely gotten to know him,” Stretch snarled. “All you know is what you’ve liked while using him! You just want an Omega to have a personal slut!”

“Stretch!” Blue gasped, tears beading in his sockets as Onyx pulled him close, letting the small skeleton hide his face against her as regret already overtook Stretch’s expression.

“That…” Onyx growled. “Was a lowball, and you better fucking know it.”

“Sorry, I just…” Stretch hesitated, growling faintly. “Fuck, just...Blue, I’m sorry, I didn’t mean to imply that about you…”

“It’s one thing to be upset at me,” Onyx started, “for wanting your brother to be claimed by me. I’m sure other Alpha have tried, perhaps even a few who were less than considerate on if Blue wanted to be claimed. Regardless, that wouldn’t be Blue’s fault. I don’t want to use him like that; plain and simple. Being able to help him during his heat, and have some fun during my own, even if it was to help him then too, doesn’t mean I want him for just that. I don’t need to explain myself to you, and you don’t need to explain yourself to me. But do not, I repeat, do not  _ ever  _ blame an Omega for how they’re treated or used by their Alpha.”

“I know that!” Stretch growled, before quieting down. “I’m sorry, I mean it. Just...Blue...are you sure you’re okay with this?”

Blue sniffled faintly, looking up hesitantly as he wiped away the tears, glancing towards Red and Edge before looking down at his lap. Onyx let him sit up on his own away from her, looking towards him as well.

“Yes...I’m okay with it…” Blue mumbled. “Onyx...has respected me not wanting to be claimed, and eventually...maybe I’d like her to claim me. It’d be...nice if you two got along.”

Stretch looked pained at that, glancing at Edge before looking back to Onyx.

“That’s something I can do.”

**Author's Note:**

> Make sure to come follow me on Twitter if you like art content as well! I'm mainly retweeting stuff, kinda of lacking in the Undertale art department recently.
> 
> SFW: https://twitter.com/OnyxianDrake
> 
> NSFW 18+(Your age has to be visible!!): https://twitter.com/UnholyLiar


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